The ends of the common bile duct and pancreatic duct and the periphery of the jugular abdomen are each surrounded by a circular sphincter called the sphincter of the common bile duct, the sphincter of the pancreatic duct, and the sphincter of the jugular abdomen, respectively. The three parts of the sphincter together constitute the sphincter of Oddi, which contains circular, longitudinal and oblique rows of smooth muscle fibers. Under the innervation of visceral nerves and hormones, it plays an important function of regulating the flow of bile and pancreatic juice, preventing the mutual traffic between bile and pancreatic juice, and preventing the reflux of duodenal contents. 1. Sphincter of the common bile duct: a ring-shaped muscle, located at the end of the common bile duct, is its strongest muscle fiber, contraction can make the lower end of the common bile duct closed. 2. Pancreatic duct sphincter: at the end of the pancreatic duct, some of them may be incomplete, performance is missing, affecting the closure of the pancreatic duct. 3. Sphincter of the jugular abdomen: composed of the continuation part of the longitudinal duodenal muscle fibers and the circular muscle fibers, its abnormal contraction can make the bile flow backward to the pancreatic duct through the jugular abdomen. The three sections of sphincter have fine structure and important function, and the consequences of lesions are serious, which need timely and standardized treatment.